A seat assembly for a motor vehicle seat comprises a seat element constituting a component of a seat structure of a motor vehicle seat, a tubular drive element (drive tube) connected pivotably (around its longitudinal axis) to the seat element constituting a component of a displacement arrangement for an adjustable seat part (such as a height adjustable seat cushion), as well as a weight sensor (which in an exemplary embodiment is electrically operated) for the detection of seat occupancy using the weight of a person sitting in the corresponding motor vehicle seat. Through the detection of seat occupancy, it is possible to control various functional groups of a motor vehicle as a function of that seat occupancy such as for example, automatic occupancy- and/or weight-dependent adjustment of certain seat components as well as the occupancy- and/or weight-dependent deployment of an airbag module.